Other countries near Russia could also face aggression if President Vladimir Putin is allowed to get away with his actions in Ukraine, former U.S. Secretary of State Hillary Clinton said Tuesday.

Clinton, a potential 2016 presidential contender, called Russia's move to annex Crimea illegal and a violation of international law.

"If he's allowed to get away with that, I think you'll see a lot of other countries either directly facing Russian aggression or suborned with their political systems so that they are so intimidated that in effect they are transformed into vassals, not sovereign democracies,'' Clinton said at an event hosted by the Board of Trade of Metropolitan Montreal at the Palais des Congres.

In response to a question about Ukraine, Clinton advocated a ``two-track'' approach toward resolving the crisis that included economic incentives and ``standing up for our values.''

Along with sanctions against Russia, Clinton argued for increased financial and technical support for a democratic government in Kiev.

She also said Europe needs to be encouraged to find other energy sources so they aren't dependent on Russian oil and gas.

"We don't have to be rattling sabers and all that. That's not useful,'' she said.

"But people need to get moving in protecting themselves against future intimidation. It might take a year, it might take two years, but it needs to be slow and steady. And then once again people will see the difference, they will see the choices.''

Clinton referred to the conflict as a "clash of values'' and "an effort by Putin to rewrite the boundaries of post-World War II Europe.''

"We're going to stand up against illegal acts and we're going to demonstrate that we have a better model, just like we did for 50 years. That takes continuity and persistence and it takes a consensus across the political spectrum in our country, certainly,'' she said.

Clinton said she's hopeful another Cold War can be avoided.

"Obviously nobody wants to see that. I think that's primarily up to Putin.''

Earlier this month, Clinton likened Putin's actions on the Crimean Peninsula to those of Adolf Hitler in the 1930s. She has also said he is a tough but thin-skinned leader who is squandering his country's potential.